Industry status and wastewater characteristics

China has a population of about 1.4 billion, and there is a high demand for disease treatment, rehabilitation and healthcare, which has led to numerous pharmaceutical industries. In recent years, with the increasing aging population in China, the new population has also been increasing, greatly accelerating the development of China's pharmaceutical industry. At the same time, pharmaceutical wastewater generated by the pharmaceutical process is constantly presented to the general public, becoming one of the important pollution sources that affect people's living environment. The key to solving the problem is how to effectively treat pharmaceutical wastewater and how to adopt effective treatment technologies.

Pharmaceutical wastewater is the wastewater produced by pharmaceutical factories when producing traditional Chinese patent medicines and simple preparations or western medicine. Pharmaceutical wastewater mainly includes antibiotic production (biopharmaceutics) wastewater, synthetic drug production (chemical pharmaceuticals) wastewater, traditional Chinese patent medicines and simple preparations production wastewater, as well as washing water and flushing wastewater in the production process of various preparations.

The production process of drugs determines the characteristics of pharmaceutical wastewater. The production of drugs is achieved through chemical synthesis processes and separation and purification from medicinal plants to obtain raw materials. Due to the different types of drugs, production processes, and complex processes, there are many types of raw and auxiliary materials. The production process strictly controls the quality of raw materials and intermediates, resulting in low net material yield and many by-products. As a result, pharmaceutical wastewater has significant differences in composition, complex components, high levels of pollutants, high COD, low and fluctuating BOD5 and CODcr ratioses, The characteristics of poor biodegradability, high levels of difficult to degrade substances, strong toxicity, intermittent discharge, large fluctuations in water quantity, quality, and types of pollutants have brought great difficulties to governance.

Although pharmaceutical wastewater has varying water quality due to different products, raw materials, and process methods, overall, pharmaceutical wastewater has a high content of organic pollutants, toxic substances, difficult to biodegrade substances, and high salt content. It is a highly hazardous industrial wastewater, and arbitrary discharge can cause great harm to the environment

Main hazards

1. Chemical reactions occur between pollutants in pharmaceutical wastewater or with substances in water bodies, resulting in new pollution. For example, nitrosamines are a strong carcinogen. If the wastewater contains substances such as oxytetracycline, piperazine, morpholine, and aminoaspirin, it can react with sodium nitrite in an acidic medium to produce dimethylnitrosamine.

2. When organic matter undergoes biological oxidation and decomposition in water, it consumes dissolved oxygen in the water. Excessive organic matter content can cause hypoxia or deoxygenation in the water, resulting in the death of aerobic aquatic organisms in the water. Anaerobic microorganisms proliferate in large numbers, and anaerobic digestion produces substances such as methane, hydrogen sulfide, alcohols, ammonia, and amines, further inhibiting aquatic organisms and making the water black and odorous.

3. Some pesticides and their synthetic intermediates often have certain bactericidal or antibacterial effects, thereby affecting the metabolism of microorganisms such as bacteria and algae in water bodies, and ultimately disrupting the overall ecosystem balance of this water body. For example, when water contains penicillin, tetracycline, and chloramphenicol, it can inhibit the growth of green algae.

Pharmaceutical classification and composition analysis

The national pharmaceutical industry mainly includes biopharmaceuticals, chemical pharmaceuticals and Chinese herbal medicine production, corresponding to the above mentioned wastewater from antibiotic production, synthetic drug production (chemical pharmaceuticals), and traditional Chinese patent medicines and simple preparations production.

Biopharmaceuticals use microorganisms to ferment, filter, and extract various organic raw materials, thereby producing various antibiotics, amino acids, and some pharmaceutical intermediates; Chemical pharmaceuticals use chemical reaction processes to produce pharmaceutical intermediates and synthetic drugs from organic and inorganic raw materials; The production of Chinese herbal medicine refers to the processing of Chinese herbal medicine, the extraction of preparations or traditional Chinese patent medicines and simple preparations. The production process mainly includes the pretreatment of raw materials and the extraction of preparations. The source and composition of wastewater are summarized in the table below.

Common treatment methods for pharmaceutical wastewater

The treatment methods for pharmaceutical wastewater can be summarized as follows: physicochemical treatment, chemical treatment, biochemical treatment, and a combination of multiple methods. Each treatment method has its own advantages and disadvantages.

1、 Chemical treatment

When applying chemical methods, excessive use of certain reagents can easily lead to secondary pollution of water bodies, so relevant experimental research work should be done well before design. Chemical methods include iron carbon method, chemical redox method (Fenton reagent, H2O2, O3), deep oxidation technology, etc.

Oxidation method

Adopting this method can improve the biodegradability of wastewater and have a good removal rate of COD. The results of ozone oxidation treatment on three types of antibiotic wastewater showed that the wastewater treated with ozone oxidation not only improved the BOD5/COD ratio, but also had a COD removal rate of over 80%.

Fenton reagent treatment method

The combination of ferrous salts and H2O2 is called Fenton reagent, which can effectively remove difficult to degrade organic compounds that cannot be removed by traditional wastewater treatment techniques. With the deepening of research, ultraviolet light (UV) and oxalate (C2O42-) were introduced into Fenton reagents, greatly enhancing their oxidation ability. Using TiO2 as a catalyst and 9W low-pressure mercury lamp as a light source, Fenton reagent was used to treat pharmaceutical wastewater. The decolorization rate was 98%, COD removal rate was 93.5%, and nitrobenzene compounds decreased from 8.15mg/L to 0.43mg/L.

Iron charcoal method

Industrial operation has shown that using Fe-C as a pre-treatment step for pharmaceutical wastewater can greatly improve the biodegradability of its effluent. The combined treatment process of iron charcoal micro electrolysis anaerobic aerobic air flotation is used to treat pharmaceutical intermediate production wastewater such as erythromycin and ciprofloxacin hydrochloride. The COD removal rate after iron charcoal treatment reaches 25%, and the final effluent meets the first level standard of the national "Comprehensive Wastewater Discharge Standard" (GB8978-1996).

Oxidation technology

Also known as Advanced oxidation process, it gathers the latest research results of modern light, electricity, sound, magnetism, materials and other similar disciplines, mainly including electrochemical oxidation, wet oxidation, supercritical water oxidation, photocatalytic oxidation and ultrasonic degradation. Among them, ultraviolet photocatalytic oxidation technology has advantages such as novelty, efficiency, and no selectivity to wastewater, especially suitable for the degradation of unsaturated hydrocarbons. The reaction conditions are also relatively mild, and there is no secondary pollution, which has good application prospects. Compared with UV, heat, pressure and other treatment methods, ultrasonic treatment of organic matter is more direct and requires lower equipment requirements. As a new type of treatment method, it is receiving more and more attention. Pharmaceutical wastewater was treated by ultrasonic aerobic biological Contact process method. Under the condition of ultrasonic treatment for 50s and power of 200w, the total COD removal rate of wastewater reached 95%.

2、 Physicochemical treatment

According to the water quality characteristics of pharmaceutical wastewater, it is necessary to use physicochemical treatment as a pre-treatment or post-treatment process for biochemical treatment during its treatment process. The current physical and chemical treatment methods mainly include coagulation, air flotation, adsorption, ammonia stripping, electrolysis, ion exchange, and membrane separation.

Air flotation method

The air flotation method usually includes various forms such as inflatable air flotation, dissolved air flotation machine, chemical air flotation, and electrolytic air flotation. The CAF concave air flotation device is used for pre-treatment of pharmaceutical wastewater, and the average removal rate of COD is about 20% with appropriate reagent coordination.

Adsorption method

Commonly used adsorbents include activated carbon, activated coal, humic acids, adsorption resins, etc. Using coal ash adsorption two-stage aerobic biological treatment process to treat its wastewater. The results showed that the adsorption pretreatment achieved a COD removal rate of 43% and increased the BOD5/COD value of the wastewater.

Coagulation method

This technology is currently a widely used water quality treatment method both domestically and internationally. It is widely used in the pre-treatment and post-treatment processes of pharmaceutical wastewater, such as aluminum sulfate and polymeric iron sulfate, for traditional Chinese medicine wastewater. The key to efficient coagulation treatment lies in the appropriate selection and addition of high-performance coagulants. In recent years, the development direction of coagulants has shifted from low molecular weight to polymeric polymers, and from single component functional type to composite type. Liu Minghua et al. used an efficient composite flocculant F-1 developed by him to treat wastewater from the production of emergency syrup. At a pH of 7.0 and a flocculant dosage of 300mg/L, the removal rates of COD, SS, and chromaticity in the wastewater reached 69.9%, 96.8%, and 88.8%, respectively. Its performance was significantly superior to single flocculants such as PAC (powdered activated carbon) and polyacrylamide (PAM).

Membrane separation method

Membrane technology includes reverse osmosis, nanofiltration membranes, and fiber membranes, which can recover useful substances and reduce the total amount of organic matter emissions. The main characteristics of this technology are simple equipment, convenient operation, no phase change or chemical changes, high processing efficiency, and energy conservation. The separation experiment of lincomycin wastewater using nanofiltration membrane found that it not only reduced the inhibitory effect of lincomycin on microorganisms in the wastewater, but also recovered lincomycin.

Electrolytic method

This method for treating wastewater has attracted attention due to its high efficiency and ease of operation, while the electrolysis method also has good decolorization effect. The electrolysis method was used to pretreat the riboflavin supernatant, and the removal rates of COD, SS, and chromaticity reached 72%, 84%, and 67%, respectively.

3、 Biochemical treatment

Biochemical treatment technology is currently widely used in the treatment of pharmaceutical wastewater, including aerobic biological method, anaerobic biological method, aerobic anaerobic combination method, and other methods.

Aerobic biological treatment

Due to the fact that pharmaceutical wastewater is mostly high concentration organic wastewater, it is generally necessary to dilute the original solution during aerobic biological treatment, resulting in high power consumption and poor biodegradability of the wastewater. It is difficult to directly discharge the wastewater after biochemical treatment to meet the standard. Therefore, there are not many cases where aerobic treatment is used alone, and pre-treatment is generally required. The commonly used aerobic biological treatment methods include activated sludge method, deep well aeration method, adsorption biodegradation method (AB method), contact oxidation method, sequencing batch batch batch activated sludge method (SBR method), circulating activated sludge method (CASS method), etc.

Biological contact oxidation method

This technology combines the advantages of activated sludge and biofilm methods, and has the advantages of high volumetric load, low sludge production, strong impact resistance, stable process operation, and convenient management. Many projects adopt a two-stage approach with the aim of domesticating dominant bacterial species at different stages, fully leveraging the synergistic effects between different microbial populations, and improving biochemical effects and impact resistance. In engineering, anaerobic digestion and acidification are often used as pretreatment processes, and contact oxidation method is used to treat pharmaceutical wastewater.

Deep well aeration method

Deep well aeration is a high-speed activated sludge system, which has the advantages of high oxygen utilization rate, small footprint, good treatment effect, low investment, low operating costs, no sludge bulking, and low sludge production. In addition, its insulation effect is good, and the treatment is not affected by climate conditions, which can ensure the effectiveness of winter wastewater treatment in northern regions. After biochemical treatment in a deep well aeration tank, the COD removal rate of high concentration organic wastewater reaches 93.5%, indicating that its treatment efficiency is very high and extremely beneficial for the next step of treatment, playing a decisive role in meeting the effluent standards of process treatment.

SBR method

The SBR method has the advantages of strong impact load resistance, high sludge activity, simple structure, no reflux, flexible operation, less land occupation, low investment, stable operation, high substrate removal rate, and good nitrogen and phosphorus removal effect. It is suitable for treating wastewater with large fluctuations in water quantity and quality. The experiment of treating pharmaceutical wastewater using SBR process shows that aeration time has a significant impact on the treatment effect of this process; Setting up anoxic sections, especially repeating the design of alternating anoxic and aerobic processes, can significantly improve the treatment effect; The SBR enhanced treatment process with the addition of PAC in the reaction tank can significantly improve the removal efficiency of the system. In recent years, this process has become increasingly perfect and has been widely used in the treatment of pharmaceutical wastewater. The hydrolysis acidification SBR method is used to treat biopharmaceutical wastewater, and the effluent quality meets the first level standard of GB8978-1996.

AB method

The AB method belongs to the ultra-high load activated sludge method. The removal efficiency of BOD5, COD, SS, phosphorus, and ammonia nitrogen by AB process is generally higher than that of conventional activated sludge method. Its outstanding advantages are high load in section A, strong resistance to impact load, and significant buffering effect on pH and toxic substances. It is particularly suitable for treating wastewater with high concentration and significant changes in water quality and quantity. The hydrolysis acidification AB biological process is used to treat antibiotic wastewater, which has a short process flow, energy saving, and lower treatment cost than the chemical flocculation biological method for the same type of wastewater.

Anaerobic biological treatment

At present, anaerobic treatment is the main method for treating high concentration organic wastewater both domestically and internationally. However, the COD of the effluent after separate anaerobic treatment is still high, and post-treatment (such as aerobic biological treatment) is generally required. At present, it is still necessary to strengthen the development and design of efficient anaerobic reactors and conduct in-depth research on operating conditions. The successful applications in the treatment of pharmaceutical wastewater include upflow anaerobic sludge bed (UASB), anaerobic composite bed (UBF), anaerobic baffled reactor (ABR), hydrolysis method, etc.

Hydrolysis acidification method

The full name of hydrolysis tank is Hydrolysis Upflow Sludge Bed (HUSB), which is an improved UASB. Compared to the full process anaerobic tank, the hydrolysis tank has the following advantages: no need for sealing, stirring, and no three-phase separator, reducing cost and facilitating maintenance; It can degrade large molecules and non biodegradable organic matter in sewage into small molecules and easily biodegradable organic matter, improving the biodegradability of raw water; Rapid response, small tank size, low infrastructure investment, and ability to reduce sludge volume. In recent years, the hydrolysis aerobic process has been widely applied in the treatment of pharmaceutical wastewater. For example, a biopharmaceutical factory has adopted the hydrolysis acidification two-stage biological contact oxidation process to treat pharmaceutical wastewater, which runs stably and has significant organic matter removal effects. The removal rates of COD, BOD5, and SS are 92.0%, 91.5%, and 85.6%, respectively.

UASB method

UASB reactor has the advantages of high anaerobic digestion efficiency, simple structure, short hydraulic retention time, and no need for additional sludge reflux device. When using UASB method to treat pharmaceutical production wastewater such as kanamycin, chloramphenicol, VC, SD, and glucose, it is usually required that the SS content should not be too high to ensure a COD removal rate of over 82% to 90%. The COD removal rate of two-stage series UASB can reach over 92%.

UBF method

A comparative experiment was conducted between UASB and UBF, and the results showed that UBF has the characteristics of good mass transfer and separation efficiency of the reaction liquid, large biomass and multiple biological species, high treatment efficiency, and strong operational stability. It is a practical and efficient anaerobic bioreactor.

Anaerobic aerobic and other combined treatment processes

Due to the fact that individual aerobic or anaerobic treatments often fail to meet the requirements, combined processes such as anaerobic aerobic and hydrolytic acidification aerobic have shown significant advantages over single treatment methods in improving the biodegradability, impact resistance, investment cost, and treatment efficiency of wastewater. Therefore, they have been widely applied in engineering practice. The anaerobic aerobic process was used to treat pharmaceutical wastewater, with a BOD5 removal rate of 95% and a COD removal rate of 96%. The treatment effect was stable; The micro electrolysis anaerobic hydrolysis acidification SBR process is used to treat chemical synthesis pharmaceutical wastewater. The results show that the entire series process has strong impact resistance to changes in wastewater quality and water volume, and the COD removal rate can reach 85% to 92%. It is an ideal process choice for treating pharmaceutical wastewater; In the treatment of pharmaceutical intermediate wastewater, the hydrolysis acidification A/O catalytic oxidation contact oxidation process is used. When the influent COD is about 12000mg/L, the effluent COD reaches below 280mg/L; The use of biofilm SBR method to treat pharmaceutical wastewater containing biologically difficult to degrade substances can achieve a COD removal rate of 88.5% to 98.5%, which is much higher than the treatment effect of separate biofilm and SBR methods.

In addition, with the continuous development of membrane technology, the application research of membrane bioreactor (MBR) in pharmaceutical wastewater treatment is gradually deepening. MBR combines the characteristics of membrane separation technology and biological treatment, and has the advantages of high volume load, strong impact resistance, small footprint, and low residual sludge. The anaerobic membrane bioreactor process was used to treat pharmaceutical intermediate acyl chloride wastewater with a COD of 24000mg/L, and the system maintained a COD removal rate of over 95%; Utilizing the ability of specialized bacteria to degrade specific organic matter, an extraction membrane bioreactor was first used to treat industrial wastewater containing 3,4-dichloroaniline. The HRT was 2.5 hours, and the removal rate reached 99%, achieving ideal treatment results. Although there are still problems with membrane fouling, with the continuous development of membrane technology, MBR will be more widely used in the field of pharmaceutical wastewater treatment.

Integrated sewage treatment equipment

Recommended treatment by Hongjie Water 

The water quality characteristics of pharmaceutical wastewater make it impossible for most pharmaceutical wastewater to meet the standard by using biochemical treatment alone, so necessary pre-treatment must be carried out before biochemical treatment. Generally, a regulating tank should be set up to regulate the water quality, quantity, and pH, and a certain physicochemical or chemical method should be used as a pre-treatment process according to the actual situation to reduce SS, salinity, and some COD in the water, reduce biological inhibitory substances in the wastewater, and improve the biodegradability of the wastewater, in order to facilitate subsequent biochemical treatment of the wastewater.

After pre-treatment, certain anaerobic and aerobic processes can be selected for treatment based on their water quality characteristics. If the effluent requirements are high, further post-treatment is required after the aerobic treatment process. The selection of specific processes should comprehensively consider factors such as the nature of wastewater, the treatment effect of the process, infrastructure investment, and operation and maintenance, to achieve technical feasibility and economic rationality. The overall process route is a combination of pre-treatment, anaerobic, aerobic, and post-treatment processes. The combined process of hydrolysis adsorption contact oxidation filtration is used to treat comprehensive pharmaceutical wastewater containing artificial insulin, etc. The treated effluent quality is superior to the first level standard of GB8978-1996. The air floatation hydrolysis contact oxidation process has achieved good treatment results for chemical pharmaceutical wastewater, the composite micro oxygen hydrolysis composite aerobic sand filtration process for antibiotic wastewater, and the air floatation UBF-CASS process for high concentration traditional Chinese medicine extraction wastewater.

Shenzhen Hongjie Water Technology Co., Ltd. is located in the national economic center city of Shenzhen, Guangdong. It is a sewage treatment company that integrates technology research and development, project design, equipment manufacturing, engineering installation, commissioning and operation, technical consulting services, and after-sales service. It can meet the needs of the domestic wastewater treatment market and combine the design concepts of domestic and foreign wastewater treatment products, Integrating advanced foreign wastewater treatment technology and exquisite production processes into the wastewater treatment system of Hongjie Water, and subsequently developing and innovating, the product has been highly trusted by consumers since it was put into the market.

The company mainly engages in the design, manufacturing, installation, debugging, and maintenance of various water treatment equipment, including pure water equipment, ultra pure water equipment, reverse osmosis equipment, GMP purified water equipment, EDI deionized water equipment, softened water equipment, and reclaimed water reuse equipment, sewage and wastewater treatment equipment, all of which are integrated into an environmentally friendly high-tech manufacturer. For many years, we have been committed to researching and innovating sewage treatment equipment, striving for excellence; Boost the advancement of water treatment technology and the manufacturing industry.

The company has strong technical strength and a group of scientific and technological personnel dedicated to the water treatment industry, possessing safety production licenses, safety standardization enterprises, more than 10 utility model patents, quality management systems, environmental management systems, and occupational health and safety management system certification certificates. Simultaneously obtaining multiple honorary certificates; We have an experienced design and computing team, a high-level and high-quality production team, supporting highly professional service personnel, and a meticulous, efficient, and responsive after-sales team.